When and why to use overlap weighting: clarifying its role, assumptions, and estimand in real-world studies

Overlap weighting is a statistical method used in health research to compare treatments when people are not randomly assigned to different options. It focuses on patients who could realistically receive either treatment and helps improve the fairness and precision of comparisons. However, the results apply only to this specific group and not everyone in the study. Researchers should choose this method only when it fits the question they are asking.